Add documentation about the `exec_compatible_with` attribute.

Fixes #6558.

Closes #6564.

PiperOrigin-RevId: 220275163
diff --git a/site/docs/platforms.md b/site/docs/platforms.md
index 8935ebb..4c3079e 100644
--- a/site/docs/platforms.md
+++ b/site/docs/platforms.md
@@ -27,8 +27,7 @@
 for build actions. Platforms can also be used in combination with the
 [config_setting](be/general.html#config_setting)
 rule to write
-  <a href="https://docs.bazel.build/versions/master/configurable-attributes.html">
-  configurable attributes</a>.
+<a href="configurable-attributes.html"> configurable attributes</a>.
 
 Bazel recognizes three roles that a platform may serve: